<template>
  <section class="pointers-container">
    <section id='a-box'>
      <div class="profile-img" :style="{opacity:1-state.scrollHeight*0.05}">
        <img class="profile-logo"
             :src="state.websiteInfo.avatar"
             alt="logo">
      </div>
      <h2 class='a-second-title' :style="{opacity:1-state.scrollHeight*0.05}">Hello! I'm
        {{ state.websiteInfo.name || 'ZHOU YI' }}</h2>
      <p class='a-second-title-sub' :style="{opacity:1-state.scrollHeight*0.05}">{{ state.websiteInfo.mottoTop }}</p>
      <canvas></canvas>
    </section>
    <div class="scroll-hint-box" @click="emits('mose','about')">
      <div class="scroll-hint"></div>
    </div>
  </section>
</template>


<script setup>

import {frontendsetups} from "../api/modules/api.common";
const emits = defineEmits(['mose'])
const state = reactive({
  scrollHeight: 0,
  setting: {},
  websiteInfo: {},
  theme: {},
})
const handleScrollHeight = () => {
  state.scrollHeight = window.scrollY * 0.05
}
const getFrontendSetups = async () => {
  let res = await frontendsetups({})
  state.setting = res.data.result[0] || {}
  state.websiteInfo = res.data.result[0].websiteInfo || {}
  state.theme = res.data.result[0].theme || {}
}
getFrontendSetups()
onMounted(() => {
  // 始化和获取WebGL上下文:
  const canvas = document.getElementsByTagName('canvas')[0];
  canvas.width = canvas.clientWidth;
  canvas.height = canvas.clientHeight;

  let config = {
    TEXTURE_DOWNSAMPLE: 1,
    DENSITY_DISSIPATION: 0.98,
    VELOCITY_DISSIPATION: 0.99,
    PRESSURE_DISSIPATION: 0.8,
    PRESSURE_ITERATIONS: 25,
    CURL: 28,
    SPLAT_RADIUS: 0.004
  };


  let pointers = [];
  let splatStack = [];

  const {gl, ext} = getWebGLContext(canvas);

  function getWebGLContext(canvas) {
    const params = {alpha: false, depth: false, stencil: false, antialias: false};

    let gl = canvas.getContext('webgl2', params);
    const isWebGL2 = !!gl;
    if (!isWebGL2)
      gl = canvas.getContext('webgl', params) || canvas.getContext('experimental-webgl', params);

    let halfFloat;
    let supportLinearFiltering;
    if (isWebGL2) {
      gl.getExtension('EXT_color_buffer_float');
      supportLinearFiltering = gl.getExtension('OES_texture_float_linear');
    } else {
      halfFloat = gl.getExtension('OES_texture_half_float');
      supportLinearFiltering = gl.getExtension('OES_texture_half_float_linear');
    }
    // let captureFolder = gl.addFolder('Capture');
    // captureFolder.addColor(0.0, 0.0, 0.0, 1.0);
    // gl.clearColor(0.0, 0.0, 0.0, 1.0);
    gl.clearColor(1.0, 1.0, 1.0, 1.0);

    const halfFloatTexType = isWebGL2 ? gl.HALF_FLOAT : halfFloat.HALF_FLOAT_OES;
    let formatRGBA;
    let formatRG;
    let formatR;

    if (isWebGL2) {
      formatRGBA = getSupportedFormat(gl, gl.RGBA16F, gl.RGBA, halfFloatTexType);
      formatRG = getSupportedFormat(gl, gl.RG16F, gl.RG, halfFloatTexType);
      formatR = getSupportedFormat(gl, gl.R16F, gl.RED, halfFloatTexType);
    } else {
      formatRGBA = getSupportedFormat(gl, gl.RGBA, gl.RGBA, halfFloatTexType);
      formatRG = getSupportedFormat(gl, gl.RGBA, gl.RGBA, halfFloatTexType);
      formatR = getSupportedFormat(gl, gl.RGBA, gl.RGBA, halfFloatTexType);
    }

    return {
      gl,
      ext: {
        formatRGBA,
        formatRG,
        formatR,
        halfFloatTexType,
        supportLinearFiltering
      }
    };


  }

  function getSupportedFormat(gl, internalFormat, format, type) {
    if (!supportRenderTextureFormat(gl, internalFormat, format, type)) {
      switch (internalFormat) {

        case gl.R16F:
          return getSupportedFormat(gl, gl.RG16F, gl.RG, type);
        case gl.RG16F:
          return getSupportedFormat(gl, gl.RGBA16F, gl.RGBA, type);
        default:
          return null;
      }

    }

    return {
      internalFormat,
      format
    };

  }

  function supportRenderTextureFormat(gl, internalFormat, format, type) {
    let texture = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, texture);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
    gl.texImage2D(gl.TEXTURE_2D, 0, internalFormat, 4, 4, 0, format, type, null);

    let fbo = gl.createFramebuffer();
    gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
    gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);

    const status = gl.checkFramebufferStatus(gl.FRAMEBUFFER);
    if (status != gl.FRAMEBUFFER_COMPLETE)
      return false;
    return true;
  }

  function pointerPrototype() {
    this.id = -1;
    this.x = 0;
    this.y = 0;
    this.dx = 0;
    this.dy = 0;
    this.down = false;
    this.moved = false;
    this.color = [30, 0, 300];
  }

  pointers.push(new pointerPrototype());

  class GLProgram {
    constructor(vertexShader, fragmentShader) {
      this.uniforms = {};
      this.program = gl.createProgram();

      gl.attachShader(this.program, vertexShader);
      gl.attachShader(this.program, fragmentShader);
      gl.linkProgram(this.program);

      if (!gl.getProgramParameter(this.program, gl.LINK_STATUS))
        throw gl.getProgramInfoLog(this.program);

      const uniformCount = gl.getProgramParameter(this.program, gl.ACTIVE_UNIFORMS);
      for (let i = 0; i < uniformCount; i++) {
        const uniformName = gl.getActiveUniform(this.program, i).name;
        this.uniforms[uniformName] = gl.getUniformLocation(this.program, uniformName);
      }
    }

    bind() {
      gl.useProgram(this.program);
    }
  }


  function compileShader(type, source) {
    const shader = gl.createShader(type);
    gl.shaderSource(shader, source);
    gl.compileShader(shader);

    if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS))
      throw gl.getShaderInfoLog(shader);

    return shader;
  }

  //********定义着色器程序  顶点着色器代码**********
  const baseVertexShader = compileShader(gl.VERTEX_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    attribute vec2 aPosition;
    varying vec2 vUv;
    varying vec2 vL;
    varying vec2 vR;
    varying vec2 vT;
    varying vec2 vB;
    uniform vec2 texelSize;

    void main () {
        vUv = aPosition * 0.5 + 0.5;
        vL = vUv - vec2(texelSize.x, 0.0);
        vR = vUv + vec2(texelSize.x, 0.0);
        vT = vUv + vec2(0.0, texelSize.y);
        vB = vUv - vec2(0.0, texelSize.y);
        gl_Position = vec4(aPosition, 0.0, 1.0);
    }
`);
  //定义着色器程序  // 清除着色器代码
  const clearShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    uniform sampler2D uTexture;
    uniform float value;

    void main () {
        gl_FragColor = value * texture2D(uTexture, vUv);
    }
`);

  const displayShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    uniform sampler2D uTexture;

    void main () {
       gl_FragColor = texture2D(uTexture, vUv);
        //  gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
    }
`);

  const splatShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    uniform sampler2D uTarget;
    uniform float aspectRatio;
    uniform vec3 color;
    uniform vec2 point;
    uniform float radius;

    void main () {
        vec2 p = vUv - point.xy;
        p.x *= aspectRatio;
        vec3 splat = exp(-dot(p, p) / radius) * color;
        vec3 base = texture2D(uTarget, vUv).xyz;
        gl_FragColor = vec4(base + splat, 1.0);
    }
`);

  const advectionManualFilteringShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    uniform sampler2D uVelocity;
    uniform sampler2D uSource;
    uniform vec2 texelSize;
    uniform float dt;
    uniform float dissipation;

    vec4 bilerp (in sampler2D sam, in vec2 p) {
        vec4 st;
        st.xy = floor(p - 0.5) + 0.5;
        st.zw = st.xy + 1.0;
        vec4 uv = st * texelSize.xyxy;
        vec4 a = texture2D(sam, uv.xy);
        vec4 b = texture2D(sam, uv.zy);
        vec4 c = texture2D(sam, uv.xw);
        vec4 d = texture2D(sam, uv.zw);
        vec2 f = p - st.xy;
        return mix(mix(a, b, f.x), mix(c, d, f.x), f.y);
    }

    void main () {
        vec2 coord = gl_FragCoord.xy - dt * texture2D(uVelocity, vUv).xy;
        gl_FragColor = dissipation * bilerp(uSource, coord);
        gl_FragColor.a = 1.0;
    }
`);

  const advectionShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    uniform sampler2D uVelocity;
    uniform sampler2D uSource;
    uniform vec2 texelSize;
    uniform float dt;
    uniform float dissipation;

    void main () {
        vec2 coord = vUv - dt * texture2D(uVelocity, vUv).xy * texelSize;
        gl_FragColor = dissipation * texture2D(uSource, coord);
        gl_FragColor.a = 1.0;
    }
`);

  const divergenceShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    varying vec2 vL;
    varying vec2 vR;
    varying vec2 vT;
    varying vec2 vB;
    uniform sampler2D uVelocity;

    vec2 sampleVelocity (in vec2 uv) {
        vec2 multiplier = vec2(1.0, 1.0);
        if (uv.x < 0.0) { uv.x = 0.0; multiplier.x = -1.0; }
        if (uv.x > 1.0) { uv.x = 1.0; multiplier.x = -1.0; }
        if (uv.y < 0.0) { uv.y = 0.0; multiplier.y = -1.0; }
        if (uv.y > 1.0) { uv.y = 1.0; multiplier.y = -1.0; }
        return multiplier * texture2D(uVelocity, uv).xy;
    }

    void main () {
        float L = sampleVelocity(vL).x;
        float R = sampleVelocity(vR).x;
        float T = sampleVelocity(vT).y;
        float B = sampleVelocity(vB).y;
        float div = 0.5 * (R - L + T - B);
        gl_FragColor = vec4(div, 0.0, 0.0, 1.0);
    }
`);

  const curlShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    varying vec2 vL;
    varying vec2 vR;
    varying vec2 vT;
    varying vec2 vB;
    uniform sampler2D uVelocity;

    void main () {
        float L = texture2D(uVelocity, vL).y;
        float R = texture2D(uVelocity, vR).y;
        float T = texture2D(uVelocity, vT).x;
        float B = texture2D(uVelocity, vB).x;
        float vorticity = R - L - T + B;
        gl_FragColor = vec4(vorticity, 0.0, 0.0, 1.0);
    }
`);

  const vorticityShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    varying vec2 vT;
    varying vec2 vB;
    uniform sampler2D uVelocity;
    uniform sampler2D uCurl;
    uniform float curl;
    uniform float dt;

    void main () {
        float T = texture2D(uCurl, vT).x;
        float B = texture2D(uCurl, vB).x;
        float C = texture2D(uCurl, vUv).x;
        vec2 force = vec2(abs(T) - abs(B), 0.0);
        force *= 1.0 / length(force + 0.00001) * curl * C;
        vec2 vel = texture2D(uVelocity, vUv).xy;
        gl_FragColor = vec4(vel + force * dt, 0.0, 1.0);
    }
`);

  const pressureShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    varying vec2 vL;
    varying vec2 vR;
    varying vec2 vT;
    varying vec2 vB;
    uniform sampler2D uPressure;
    uniform sampler2D uDivergence;

    vec2 boundary (in vec2 uv) {
        uv = min(max(uv, 0.0), 1.0);
        return uv;
    }

    void main () {
        float L = texture2D(uPressure, boundary(vL)).x;
        float R = texture2D(uPressure, boundary(vR)).x;
        float T = texture2D(uPressure, boundary(vT)).x;
        float B = texture2D(uPressure, boundary(vB)).x;
        float C = texture2D(uPressure, vUv).x;
        float divergence = texture2D(uDivergence, vUv).x;
        float pressure = (L + R + B + T - divergence) * 0.25;
        gl_FragColor = vec4(pressure, 0.0, 0.0, 1.0);
    }
`);

  const gradientSubtractShader = compileShader(gl.FRAGMENT_SHADER, `
    precision highp float;
    precision mediump sampler2D;

    varying vec2 vUv;
    varying vec2 vL;
    varying vec2 vR;
    varying vec2 vT;
    varying vec2 vB;
    uniform sampler2D uPressure;
    uniform sampler2D uVelocity;

    vec2 boundary (in vec2 uv) {
        uv = min(max(uv, 0.0), 1.0);
        return uv;
    }

    void main () {
        float L = texture2D(uPressure, boundary(vL)).x;
        float R = texture2D(uPressure, boundary(vR)).x;
        float T = texture2D(uPressure, boundary(vT)).x;
        float B = texture2D(uPressure, boundary(vB)).x;
        vec2 velocity = texture2D(uVelocity, vUv).xy;
        velocity.xy -= vec2(R - L, T - B);
        gl_FragColor = vec4(velocity, 0.0, 1.0);
    }
`);
  //********定义着色器程序结束 **********

  // 初始化帧缓冲对象：
  let textureWidth;
  let textureHeight;
  let density;
  let velocity;
  let divergence;
  let curl;
  let pressure;
  initFramebuffers();

  // 创建着色器程序对象
  const clearProgram = new GLProgram(baseVertexShader, clearShader);
  const displayProgram = new GLProgram(baseVertexShader, displayShader);
  const splatProgram = new GLProgram(baseVertexShader, splatShader);
  const advectionProgram = new GLProgram(baseVertexShader, ext.supportLinearFiltering ? advectionShader : advectionManualFilteringShader);
  const divergenceProgram = new GLProgram(baseVertexShader, divergenceShader);
  const curlProgram = new GLProgram(baseVertexShader, curlShader);
  const vorticityProgram = new GLProgram(baseVertexShader, vorticityShader);
  const pressureProgram = new GLProgram(baseVertexShader, pressureShader);
  const gradienSubtractProgram = new GLProgram(baseVertexShader, gradientSubtractShader);


  function initFramebuffers() {
    textureWidth = gl.drawingBufferWidth >> config.TEXTURE_DOWNSAMPLE;
    textureHeight = gl.drawingBufferHeight >> config.TEXTURE_DOWNSAMPLE;

    const texType = ext.halfFloatTexType;
    const rgba = ext.formatRGBA;
    const rg = ext.formatRG;
    const r = ext.formatR;

    density = createDoubleFBO(2, textureWidth, textureHeight, rgba.internalFormat, rgba.format, texType, ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST);
    velocity = createDoubleFBO(0, textureWidth, textureHeight, rg.internalFormat, rg.format, texType, ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST);
    divergence = createFBO(4, textureWidth, textureHeight, r.internalFormat, r.format, texType, gl.NEAREST);
    curl = createFBO(5, textureWidth, textureHeight, r.internalFormat, r.format, texType, gl.NEAREST);
    pressure = createDoubleFBO(6, textureWidth, textureHeight, r.internalFormat, r.format, texType, gl.NEAREST);
  }


  // 定义和创建帧缓冲对象和纹理
  function createFBO(texId, w, h, internalFormat, format, type, param) {
    gl.activeTexture(gl.TEXTURE0 + texId);
    let texture = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, texture);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, param);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, param);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
    gl.texImage2D(gl.TEXTURE_2D, 0, internalFormat, w, h, 0, format, type, null);

    let fbo = gl.createFramebuffer();
    gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
    gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
    gl.viewport(0, 0, w, h);
    gl.clear(gl.COLOR_BUFFER_BIT);

    return [texture, fbo, texId];
  }

  function createDoubleFBO(texId, w, h, internalFormat, format, type, param) {
    let fbo1 = createFBO(texId, w, h, internalFormat, format, type, param);
    let fbo2 = createFBO(texId + 1, w, h, internalFormat, format, type, param);

    return {
      get read() {
        return fbo1;
      },
      get write() {
        return fbo2;
      },
      swap() {
        let temp = fbo1;
        fbo1 = fbo2;
        fbo2 = temp;
      }
    };

  }


  const blit = (() => {
    gl.bindBuffer(gl.ARRAY_BUFFER, gl.createBuffer());
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([-1, -1, -1, 1, 1, 1, 1, -1]), gl.STATIC_DRAW);
    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, gl.createBuffer());
    gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array([0, 1, 2, 0, 2, 3]), gl.STATIC_DRAW);
    gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
    gl.enableVertexAttribArray(0);

    return destination => {
      gl.bindFramebuffer(gl.FRAMEBUFFER, destination);
      gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0);
    };
  })();

  let lastTime = Date.now();
  multipleSplats(parseInt(Math.random() * 20) + 5);
  update();

  // 主渲染循环和计算流体效果：
  function update() {
    resizeCanvas();


    const dt = Math.min((Date.now() - lastTime) / 1000, 0.016);
    lastTime = Date.now();

    gl.viewport(0, 0, textureWidth, textureHeight);

    if (splatStack.length > 0)
      multipleSplats(splatStack.pop());

    advectionProgram.bind();
    gl.uniform2f(advectionProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
    gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.read[2]);
    gl.uniform1i(advectionProgram.uniforms.uSource, velocity.read[2]);
    gl.uniform1f(advectionProgram.uniforms.dt, dt);
    gl.uniform1f(advectionProgram.uniforms.dissipation, config.VELOCITY_DISSIPATION);
    blit(velocity.write[1]);
    velocity.swap();

    gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.read[2]);
    gl.uniform1i(advectionProgram.uniforms.uSource, density.read[2]);
    gl.uniform1f(advectionProgram.uniforms.dissipation, config.DENSITY_DISSIPATION);
    blit(density.write[1]);
    density.swap();

    for (let i = 0; i < pointers.length; i++) {
      const pointer = pointers[i];
      if (pointer.moved) {
        splat(pointer.x, pointer.y, pointer.dx, pointer.dy, pointer.color);
        pointer.moved = false;
      }
    }

    curlProgram.bind();
    gl.uniform2f(curlProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
    gl.uniform1i(curlProgram.uniforms.uVelocity, velocity.read[2]);
    blit(curl[1]);

    vorticityProgram.bind();
    gl.uniform2f(vorticityProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
    gl.uniform1i(vorticityProgram.uniforms.uVelocity, velocity.read[2]);
    gl.uniform1i(vorticityProgram.uniforms.uCurl, curl[2]);
    gl.uniform1f(vorticityProgram.uniforms.curl, config.CURL);
    gl.uniform1f(vorticityProgram.uniforms.dt, dt);
    blit(velocity.write[1]);
    velocity.swap();

    divergenceProgram.bind();
    gl.uniform2f(divergenceProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
    gl.uniform1i(divergenceProgram.uniforms.uVelocity, velocity.read[2]);
    blit(divergence[1]);

    clearProgram.bind();
    let pressureTexId = pressure.read[2];
    gl.activeTexture(gl.TEXTURE0 + pressureTexId);
    gl.bindTexture(gl.TEXTURE_2D, pressure.read[0]);
    gl.uniform1i(clearProgram.uniforms.uTexture, pressureTexId);
    gl.uniform1f(clearProgram.uniforms.value, config.PRESSURE_DISSIPATION);
    blit(pressure.write[1]);
    pressure.swap();

    pressureProgram.bind();
    gl.uniform2f(pressureProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
    gl.uniform1i(pressureProgram.uniforms.uDivergence, divergence[2]);
    pressureTexId = pressure.read[2];
    gl.uniform1i(pressureProgram.uniforms.uPressure, pressureTexId);
    gl.activeTexture(gl.TEXTURE0 + pressureTexId);
    for (let i = 0; i < config.PRESSURE_ITERATIONS; i++) {
      gl.bindTexture(gl.TEXTURE_2D, pressure.read[0]);
      blit(pressure.write[1]);
      pressure.swap();
    }

    gradienSubtractProgram.bind();
    gl.uniform2f(gradienSubtractProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
    gl.uniform1i(gradienSubtractProgram.uniforms.uPressure, pressure.read[2]);
    gl.uniform1i(gradienSubtractProgram.uniforms.uVelocity, velocity.read[2]);
    blit(velocity.write[1]);
    velocity.swap();

    gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
    displayProgram.bind();
    gl.uniform1i(displayProgram.uniforms.uTexture, density.read[2]);
    blit(null);

    requestAnimationFrame(update);
  }

  function splat(x, y, dx, dy, color) {
    splatProgram.bind();
    gl.uniform1i(splatProgram.uniforms.uTarget, velocity.read[2]);
    gl.uniform1f(splatProgram.uniforms.aspectRatio, canvas.width / canvas.height);
    gl.uniform2f(splatProgram.uniforms.point, x / canvas.width, 1.0 - y / canvas.height);
    gl.uniform3f(splatProgram.uniforms.color, dx, -dy, 1.0);
    gl.uniform1f(splatProgram.uniforms.radius, config.SPLAT_RADIUS);
    blit(velocity.write[1]);
    velocity.swap();

    gl.uniform1i(splatProgram.uniforms.uTarget, density.read[2]);
    gl.uniform3f(splatProgram.uniforms.color, color[0] * 0.3, color[1] * 0.3, color[2] * 0.3);
    blit(density.write[1]);
    density.swap();
  }

  function multipleSplats(amount) {
    for (let i = 0; i < amount; i++) {
      const color = [Math.random() * 10, Math.random() * 10, Math.random() * 10];
      const x = canvas.width * Math.random();
      const y = canvas.height * Math.random();
      const dx = 1000 * (Math.random() - 0.5);
      const dy = 1000 * (Math.random() - 0.5);
      splat(x, y, dx, dy, color);
    }
  }

  function resizeCanvas() {
    if (canvas.width != canvas.clientWidth || canvas.height != canvas.clientHeight) {
      canvas.width = canvas.clientWidth;
      canvas.height = canvas.clientHeight;
      initFramebuffers();
    }
  }

  canvas.addEventListener('mousemove', e => {
    pointers[0].moved = pointers[0].down;
    pointers[0].dx = (e.offsetX - pointers[0].x) * 10.0;
    pointers[0].dy = (e.offsetY - pointers[0].y) * 10.0;
    pointers[0].x = e.offsetX;
    pointers[0].y = e.offsetY;
  });

  canvas.addEventListener('touchmove', e => {
    e.preventDefault();
    const touches = e.targetTouches;
    for (let i = 0; i < touches.length; i++) {
      let pointer = pointers[i];
      pointer.moved = pointer.down;
      pointer.dx = (touches[i].pageX - pointer.x) * 10.0;
      pointer.dy = (touches[i].pageY - pointer.y) * 10.0;
      pointer.x = touches[i].pageX;
      pointer.y = touches[i].pageY;
    }
  }, false);

  canvas.addEventListener('mousemove', () => {
    pointers[0].down = true;
    pointers[0].color = [Math.random() + 0.2, Math.random() + 0.2, Math.random() + 0.2];
  });

  canvas.addEventListener('touchstart', e => {
    e.preventDefault();
    const touches = e.targetTouches;
    for (let i = 0; i < touches.length; i++) {
      if (i >= pointers.length)
        pointers.push(new pointerPrototype());

      pointers[i].id = touches[i].identifier;
      pointers[i].down = true;
      pointers[i].x = touches[i].pageX;
      pointers[i].y = touches[i].pageY;
      pointers[i].color = [Math.random() + 0.2, Math.random() + 0.2, Math.random() + 0.2];
    }
  });

  window.addEventListener('mouseleave', () => {
    pointers[0].down = false;
  });

  window.addEventListener('touchend', e => {
    const touches = e.changedTouches;
    for (let i = 0; i < touches.length; i++)
      for (let j = 0; j < pointers.length; j++)
        if (touches[i].identifier == pointers[j].id)
          pointers[j].down = false;
  });


  window.addEventListener('scroll', handleScrollHeight);
})


onBeforeUnmount(() => {
  window.removeEventListener('scroll', handleScrollHeight);
});

</script>


<style lang="scss" scoped>
.pointers-container {
  font-family: courier new;
  height: 100vh;
  width: 100%;
  position: relative;

  #a-box {
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 100%;
    height: 100%;

    canvas {
      width: 100%;
      height: 100%;
    }

    .profile-img {
      width: 10rem;
      height: 10rem;
      margin: 0 auto;
      border-radius: 50%;
      overflow: hidden;
      border: 6px solid #ffffff;
      -webkit-box-shadow: 0 0 20px rgba(255, 255, 255, 0.61);
      box-shadow: 0 0 10px rgba(255, 255, 255, 1);
      position: absolute;
      left: 50%;
      top: 40%;
      transform: translateX(-50%) translateY(-50%);
      z-index: 1;

      .profile-logo {
        display: inline-block;
        width: 100%;
        height: 100%;
        z-index: 2;
        object-fit: cover;
      }
    }

    .a-second-title, .a-second-title-sub {
      position: absolute;
      left: 50%;
      top: 55%;
      transform: translateX(-50%);
      z-index: 1;
      pointer-events: none;
      -webkit-text-stroke: 1.3px white;
      letter-spacing: 1.125px;
      font-weight: 900;
      mix-blend-mode: color-dodge;
      font-family: 'Roboto', Arial, Helvetica, Sans-serif, Verdana;
      font-size: 2.5rem;
      color: #fff;
    }

    .a-second-title {
      -webkit-box-reflect: below -15px linear-gradient(transparent, rgba(0, 0, 0, .4));
    }

    .a-second-title-sub {
      left: 50%;
      top: 65%;
      font-size: 1.2rem;
      @media screen and (max-width: 768px) {
        top: 70%;
        display: none;
      }
    }
  }
}

.scroll-hint-box {
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%) translateY(-50%);

  .scroll-hint {
    margin-bottom: 20px;
    position: relative;
    height: 38px;
    width: 24px;
    border: solid 2px #fcfcfe;
    border-radius: 15px;
    cursor: pointer;
    transition: all .3s linear;

    &:hover {
      box-shadow: 0 0 20px #ffffff;
    }

    &:after {
      content: '';
      height: 4px;
      width: 4px;
      border-radius: 50%;
      background-color: #fcfcfe;
      position: absolute;
      top: 8px;
      left: calc(50% - 2px);
      animation: mouse 1s infinite
    }

    @keyframes mouse {
      0% {
        top: 8px;
        opacity: 1;
      }
      100% {
        top: 25px;
        opacity: 0;
      }
    }
  }
}


</style>
